Jack mechanism



April 30, 1957 F. R. swANsoN ET AL 2,790,361

JACK MECHANISM Filed Aug. 14, 195s Unitd States Patent JACK MECHANISM Fred R. Swanson, Walter S. Swanson, and Herman E.

Bargren, Rockford, lll., assignors to Sandstrand Machine Tool Co., a corporation of Illinois Application August 14, 1953, Serial No. 374,212

6 Claims. (Cl. 90-59) This invention relates to a jack mechanism-for supporting a work piece in a machine tool or other machine.

In machining relatively thin pieces of metal it is desirable to provide a support intermediate the ends of the work piece to prevent distortion and vibration of the machined material.

The primary object of the present invention is to provide a quick and effective means for permitting extension and locking of the jack in work supporting position, and subsequent unlocking and withdrawal of the jack from that position by -a single operating bai member.

Another object is to provide a jack mechanism having two pairs of coacting surfaces, one pair for locking the jack and operating bar member in wedge engagement, and the other pair for withdrawing the jack from work supporting position.

A further object is to provide a mechanism which will substantially eliminate bouncing laction in the jack during the machining of a work piece supported by the jack.

Other objects will become readily Iapparent from the following detailed description, taken in connection with the accompanying drawings, in which:

Fig. 1 is a vertical sectional view of a preferred form of the invention;

Fig. 2 is a vertical sectional view taken as indicated on line 2-2 of Fig. 1; and

Fig. 3 is a sectional view taken as indicated on line 3 3 of Fig. 1.

In the embodiment illustrated, the jack mechanism is secured to main frame members by use of machine bolts 11. As illustrated in Fig. l, an elongated housing 12 has a longitudinal bore 13 intersected by a transverse bore 14. The opening in an end of the bore 14 substantially coincides with an aperture 14C in the frame 10. A sleeve 14a, having a side opening 14b, is securely tted within the transverse bore 14 and the aperture 14C to slidably receive a work supporting member or jack member, generally designated 15, which supports the material A to be machined at the outwardly extending end 16 of the jack. An elongated bar 17 is adapted for reciprocable movement within the longitudinal bore, and engages the jack member through opening 14b in the sleeve to lock the jack member 15 in work engaging position and to retract it from that position. The bar is moved in one direction by the actuating means 18 and the lever arm 19, and is yieldingly urged in the opposite direction by the coiled spring 20 embracing an end of the bar. f

The jack member 15 includes a cylindrical portion 21 whose end 16 is yieldingly urged into work engaging position by the spring 22. The threaded plug 23 is inserted adjacent an end of the spring 22 to vary the tension exerted by the spring upon the cylindrical portion 21.

The jack member 15 is locked in work engaging position by the bar 17 as a result of `a pair of mating, corresponding wedging surfaces, each having two inclinations,

angle from the axis of the bar diverging away from its free end. A similar wedging surface 25 runs longitudinally of the jack member and at an langle from the axis of the jack member diverging toward its work supporting end. When the two wedging surfaces are brought slidingly into mating engagement, the jack member may be locked in a selected extended position. The jack member 15 Iand the bar 17 are held in locked engagement by the spring 20 urging the bar 17 upwardly of the housing into wedging engagement with the member 15.

Retraction of the work supporting member 15 again-st the action of spring 22 is accomplished by a pair of cam surfaces brought into engagement by the withdrawal of the bar 17 from the longitudinal bore in the housing by the actuating means 18. The cam surface 26 in the side `of the jack member runs transversely of the axis of the Y jack, and the cam surface 27 in the side of the bar 17 runs longitudinally of the bar and at lau angle diverging from the axis of the bar toward its free end. As can best be seen in Fig. l, the cam surface 26 on the work supporting member is forced inwardly of the frame 10 by the lowering of la corresponding cam `surface 27 on the elongated bar 17. These cam Surfaces and the wedging surfaces are carefully machined, so that the unlocking of the wedging surfaces occurs before the faces of the cams are brought into contact with each other.

The actuating mean-s for withdrawing 4the bar from the bore may bea pneumatic or hydraulic piston Iand cylinder, or any convenient cam arrangement whereby the actuator bar is withdrawn from the longitudinal bore in the frame. As illustrated in Fig. l, a piston rod 28 from the actuating means 18 has `a connection 29 with the lever arm 19 pivoted to the housing 10. The arm 19 has a yoked end 30 which loosely engages the threaded end 31 of the bar 17. The downward movement of the elongated bar 17 in the bore 13 may be conveniently varied by altering the position of nuts 32 and washer 33 on which the yoked end 30 of the arm 19 bears.

To place the apparatus in work supporting position, the wedging surfaces 24 and 25, are iirst withdrawn from engagement -allowing the jack member 15 to be urged outwardly against the work by the spring 22. The actuating means 18 is then released to allow the bar 17 to move upwardly under the laction of the lspring 20 to put the wedging surfaces in locking engagement. It should be noted that the work supporting member 15 is positively locked so that no bouncing action in the work supporting member 15 is possible because of the machining of the work.

To retract the jack member 15 from work engaging position, the bar 17 is lowered against the action of spring 20 by the actu-ating means 18. Initially this withdraws wedging surfaces 24 and 25 from contact and releases the jack member 15 for movement inwardly in the housing. Further lowering of bar 17 brings cam surfaces 26 and 27 into contact with one another and the jack member 15 is retracted against the action of the spring 22.

We claim:

1. A jack mechanism comprising: an elongated housing having a longitudinal bore intersected by a transverse bore; a bar mounted for reciprocatory movement in said" axis thereof, and the second of said wedging surfaces formed longitudinally in a side of said jack member and diverging toward said one end of said jack member away from the axis thereof, said pair of surfaces adapted for wedging engagement to lock said jack member in aselected extended position upon movement of said bar endwise toward said free end of the bar; a pair of coacting cam surfaces, the first of said cam surfaces formed longitudinally in a side of said bar and diverging toward said free end of said bar away from the axis thereof, and the second of said cam surfaces formed in a side of said jack member transversely of the axis of said member, said pair of cam surfaces being so arranged in relation to each other and to said pair of wedging surfaces that movement of said bar endwise away from the free end of said bar releases the wedging surfaces from locking engagement and engages said cam surfaces to draw said jack member away from engagement with a work piece; a second spring mounted within said longitudinal bore and engaging the other end of said bar normally to urge the first of said wedging surfaces into locking engagement with the second of said wedging surfaces; and positive means for providing endwise movement of said bar against the action of said first and second springs to release said wedging surfaces and withdraw said jack member from work engaging position.

2. A work supporting apparatus comprising: an elongated housing having a longitudinalbore intersected by a transverse bore; a work supporting member slidably mounted in said transverse bore and` having one end extending 'outwardly of the housing for engagement with a work piece; a spring mounted in said transverse bore normally urging said work supporting member into work engaging position; an elongated bar mounted for reciprocatory movement within said longitudinal bore and having a free end adjacent one end of the bore; a pair ef coacting cam surfaces, the first of said cam surfaces formed longitudinally in a side of said bar and diver-ging toward said free end of said bar away from the axis thereof, and the second of said cam surfaces formed in extending outwardly of the housing for engagement with a work piece; first means normally urging said work supporting member into work engaging position; an elongated bar mounted for reciprocatory movement within said longitudinal bore and having a free end adjacent one end of the bore; a pair of coacting wedging surfaces, the first of said wedging surfaces formed longitudinally in a side of said bar and diverging from the free end of said bar away from the axis thereof, and the second of said wedging surfaces formed longitudinally in a side of said work supporting member and diverging toward said one end of said work supporting member away from the axis thereof, said pair of surfaces adapted for wedging engagement to lock said work supporting member in a selected extended position upon movement of said bar endwise toward saidfree end of the bar; a pair of coacting cam surfaces, tbe first of said cam surfaces formed longitudinaiiy in a side of said bar and diverging toward said free end of said bar away from the axis thereof, and the second of said cam surfaces formed in a side of said werk supporting member transversely of the axis of said member, said pair of cam surfaces being so arranged in relation toeach other and to said pair of wedging surfaces that movement of said bar endwise away from the freev 4 end of said bar releases the wedging surfaces from lockl ing engagement and engages said cam surfaces to draw said work supporting member away from engagement with a work piece; a second means normally urging the wedging surface on said bar into locking engagement with the wedging surface on said work supporting member; and positive means for providing endwise movement of said bar against the action of said first and second means to release said wedging surfaces and withdraw said work supporting member from work engaging position.

4. A work supporting apparatus comprising: an elongated housing having a longitudinal bore intersected by a transverse bore; a work supporting member slidably mounted in said transverse bore and having one end extending outwardly of the housing for engagement with a work piece; first means normally urging said work supporting member into Work engaging position; an elongated bar mounted for reciprocatory movement within said longitudinal bore; a pair of coacting wedging surfaces, the first of said wedging surfaces formed longitudinally in a side of said bar at an angle to the axis of said bar, and the second of said wedging surfaces formed longitudinally in a side of said Work supporting member at an angle to the axis of said member, said pair of surfaces adapted for wedging engagement to lock said work supporting member in a selected extended position upon endwise movement of said bar in one direction; a pair of coacting cam surfaces, the first of said cam surfaces formed longitudinally in a side of said bar at an angle to the axis of said bar, and the second of said cam surfaces formed in a side of said work supporting member transversely of the axis of said member, said pair of cam surfaces being so arranged in relation to each other and to said pair of wedging surfaces that endwise movement of said bar in the other direction releases the wedging surfaces from locking engagement and engages said cam surfaces to draw said work supporting member away from engagement with a work piece; a second means normallyr urging the wedging surface on said bar into locking engagement with theY wedging surface on said work supporting member; and positive means for providing endwise movement of said bar against the action of said first and second means to release said wedging surfaces and withdraw said work supporting member from work engaging position. v

5. A jack mechanism comprising: a housing mounting a jack member and a bar in intersecting relation, said jack member slidably mounted in said housing and having one end extending outwardly of the housing for engagement with a work piece, and said bar mounted for reciprocatory movement in said housing in a path intersecting the path of said jack member; first means for yieldingly urging saidA jack member outwardly of the housing into work engaging position; second means for securing said jack member in a selected extended position by locklng said bar to said jack member against movement in either direction comprising a pair of coacting wedging surfaces forrned respectively on Asaid bar and on said jack member and adapted for wedging .engagement on endwise movement of said bar in one direction; third means comprising a pair of coacting cam .surfaces formed respectively on said bar and on said jack member to cause withdrawal of said jack member from work engaging position by endwise movement of said bar in the opposite direction after unlocking of said bar and said jack member; and fourth `means .to provide endwise movement of `said bar against the action of said first .means to provide said unlocking and withdrawal of the jack member.

6. A work supporting apparatus comprising: an elongated housing having `a longitudinal bore intersected by a transversebore; a work supporting member slidably mounted in said transverse bore and having one end extending outwardly `of the housing for engagement with a work piece; :rst means 'normally urging said work supporting member into work engaging position; an elongated bar mounted for reciprocatory movement within said longitudinal bore; a pair of coacting wedging surfaces, the rst of said wedging surfaces formed longitudinally in a side of said bar at an angle to the axis of said bar, and the second of said wedging surfaces formed longitudinally in a side of said work supporting member at an angle to the laxis of said member, said pair of surfaces adapted for wedging engagement to lock said work supporting member in a selected extended position upon endwise movement of said bar in one direction; and a pair of coacting cam surfaces, the rst of said cam surfacesH formed longitudinally in a side of said bar at an 'angle to the axis of said bar, and the second of said cam surfaces formed in a side of said work supporting member transversely of the axis of said member, said pair of cam surfaces being so arranged in relation to each other and to said pair of wedging surfaces that endwise movement References Cited in the le of this patent UNITED STATES PATENTS 1,438,250 Lyon Dec. 12, 1922 2,424,090 Gordinier July 15, 1947 2,593,538 Cleveland Apr. 22, 1952 

